Acquisitions and Dispositions (Schedule of Major Classes of Assets and Liabilities Held for Sale in Discontinued Operations) (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	[1]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Goodwill	$ 7,297	$ 7,405
Ullico Inc
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Goodwill	$ 108

[1] Dominion Energy’s Consolidated Balance Sheet at December 31, 2021 has been derived from the audited Consolidated Balance Sheet at that date.